Method and communication device for controlling access to a wireless access network

ABSTRACT

A method for controlling access to a wireless Access Network (AN) by a wireless communication device. The device stores a Device Access Priority (DAP) level based on characteristics of the device. When the device has data to send, the device receives an overhead message from the AN containing a Network Access Priority (NAP) parameter defining a minimum priority level for initiating network access. The device determines whether its DAP level is equal to or greater than the NAP parameter. If not, the device periodically repeats the receiving and determining steps until the stored DAP level is determined to be equal to or greater than the NAP parameter received from the AN. When the stored DAP level is equal to or greater than the NAP parameter, the device initiates network access. The device may perform and pass a Persistence Test before transmitting the data on an access channel (ACH).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority benefit under 35 U.S.C. §119(e) ofU.S. Provisional Application No. 61/625,157, filed on Apr. 17, 2012, thedisclosure of which is incorporated herein by reference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

NOT APPLICABLE

REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTINGCOMPACT DISC APPENDIX

NOT APPLICABLE

TECHNICAL FIELD

The present disclosure relates to wireless communication networks. Moreparticularly, and not by way of limitation, particular embodiments ofthe present disclosure are directed to a method and wirelesscommunication device for controlling access to a wireless Access Network(AN) by wireless communication devices, particularly Machine-to-Machine(M2M) communication devices.

BACKGROUND

In current wireless Access Networks (ANs), a wireless communicationdevice sends a signaling message or data over an Access Channel (ACH)before the network grants the device access with a dedicated channel.The ACH is usually shared among wireless devices, and congestion mayoccur on the ACH if many devices attempt to access the network within ashort period of time. In order to minimize congestion on the ACH, mostwireless technologies utilize “Persistence Test with Backoff” mechanismreferred to herein for simplicity as the “Persistence Test”.

When utilizing the Persistence Test, the wireless network usuallydefines a number of device classes. Each device class is assigned apersistence value, which is usually broadcast by the AN. Each device isconfigured to associate with a device class. When a device attempts tosend data to the AN through the ACH, the device must perform and passthe Persistence Test before the device can send any data to the AN. Thedevice generates a random persistence value and is considered to havepassed the test when the random persistence value it generated is equalto or larger than the persistence value assigned to the device'sassociated class. If the test is not passed, the device waits for a“Backoff” time period and then performs another Persistence Test with anew random value. Thus, the test essentially acts as a throttle. Eventhough a large number of devices attempt to send data within a shortperiod of time, this test can help to reduce potential ACH collisionsand hence reduce the congestion.

The Persistence Test with Backoff mechanism works well most of the timein existing wireless networks such as Global System for MobileCommunications (GSM) and Code Division Multiple Access (CDMA) networkswhere most of the calls are voice-call related or are packet-data callsthat require human intervention. However, wireless communications arechanging, and Machine-to-Machine (M2M) communication is gainingtraction. M2M communications involve communication (using wired orwireless means, or a combination of both) between two machines withouthuman intervention. It is noted here that the term “M2M communication”is also referred to as “Machine Type Communication (MTC)” in certainliterature. However, for the sake of consistency, only the term “M2Mcommunication” is used in the discussion herein. Some examples of M2Mcommunications are: smart metering (e.g., remote reading of a utilitymeter), healthcare monitoring (e.g., remote monitoring of a patient'sheart rate), agricultural monitoring (e.g., monitoring of a cropcondition), fleet management tracking (e.g., monitoring current statusof trucks on road), security surveillance (e.g., automatic, real-timemonitoring of a building or complex), billing transactions, inventorymanagement (e.g., through monitoring of Point of Sale (POS) transactionsin a supermarket) etc. These M2M communications typically use M2Mcommunications-capable sensors or diagnostic devices (which may performthe metering, monitoring, etc., mentioned earlier) on one end and an M2Muser device or receiver on the other end to receive data (e.g.,wirelessly via a cellular Access Network as discussed below withreference to FIG. 1) from the sensor devices and process the data as perdesired M2M service (e.g., utility metering service, healthcaremonitoring service, billing preparation service, etc.).

With M2M communication and M2M-type devices introduced to the market,the number of wireless devices an access network needs to support hasgrown exponentially. There are many different types of M2M devices. Someare delay tolerant while some are time critical; some may only send dataonce a month while others send data more frequently; some may be fixedwhile others are mobile. In fact, unlike a legacy wireless device (i.e.,a mobile phone including smart phone), there can be many different M2Mdevice types, each with different characteristics and accessrequirements.

One of the potential M2M device types has the time/delay tolerancecharacteristic. For example, a utility meter with wireless access can bethis type of M2M device. Depending on the application, there many suchdevices may be deployed within a small geographic area (e.g., gas meter,electricity meter). During normal operation, this type of device mayonly need to send data to the network once a day or less often. Theservice provider of these devices can also schedule the network accessfor these devices during off-peak hours so that normal wirelesscommunication is not impacted.

During normal operation, the existing Persistence Test mechanism and theconfigured communication schedule enables the network to handle a largenumber of M2M devices and does not add much burden to the network (i.e.congestion issue). But the Persistence Test mechanism is still notenough to handle possible congestion under some external events such asrecovery after a power outage. These external events may trigger a largenumber of M2M devices (for example, time tolerant devices such asutility meters) to reconnect with the network simultaneously. Even withthe Persistence Test mechanism in place, there can be large number ofdevices trying to connect to the network through the ACH at the sametime, which causes collisions and leads to RF-congestion. Large scaleRF-congestion may also lead to core network congestion.

SUMMARY

As described above, the Persistence Test mechanism essentially acts as athrottle for a device access class. Any devices belong to this accessclass have to be under the control of the persistence value for thisaccess class. The persistence value does not discriminate with respectto device access priority. There can be many devices assigned to samedevice access class, but depending on the application associated witheach device, the access priority of these devices could be different.For example, an M2M device for a water meter may have lower accesspriority compared to the access priority of an M2M device for an alarmsensor even though both devices belong to same device access class.During the congestion situation, adjusting the persistence value cancontrol the overall congestion situation of the access channel, but itdoes not discriminate whether a device should have higher or loweraccess priority from the application perspective.

To better control RF-congestion and network overload problem especiallyduring some special events, the present disclosure provides thefollowing enhancements:

Define “Device Access Priority” (DAP) levels. The DAP may be assigned toM2M devices to identify each device's access priority from a networkperspective. Different levels may be assigned to different M2M devicetypes based on the device characteristics and functionality. Forexample, the DAP level for an alarm sensor may typically be higher thanthe DAP level of a water meter.

Define “Network Access Priority” (NAP) parameter. This parameteridentifies the access priority level that is allowed to access thenetwork. If an M2M device's DAP level is less than the NAP parameterbroadcast by a serving base station, the M2M device is not allowed toinitiate a network access for a period of time. If the M2M device's DAPlevel is equal to or larger than the broadcast NAP parameter, the deviceis allowed to access the network, and the Persistence Test may be usedto determine when the device is allowed to send data over the ACH.

The NAP parameter is broadcast by the network. When the NAP parameter isnot broadcast by the network, or is set to a default value (for example,0), the prioritization feature is disabled.

The network may change the value of the NAP parameter (for example,there may be j levels for the NAP parameter) based on theloading/congestion conditions.

The DAP level for each M2M device is either pre-configured in the M2Mdevice or assigned by the network through other means (for example,during session establishment or update, over-the-air provisioning, andthe like). Devices that do not have a DAP level assigned may be viewedas having the feature disabled (i.e., the device does not need tocompare a DAP level with the NAP parameter to determine whether thedevice is allowed to access the network based on access prioritychecking).

Optionally, a DAP/NAP timer may also be implemented to function as abackoff mechanism such that if the device's configured DAP level is lessthan the NAP parameter broadcast by the network, the M2M device is notallowed to initiate a network access for a random period (or configuredperiod) of time before re-scanning the NAP parameter broadcast by thenetwork. It should be noted that instead of using a timer, the devicemay simply keep monitoring the broadcast messages that carry the NAPparameter.

After re-scanning, the M2M device is allowed to initiate a networkaccess (for example, by performing the Persistence Test) if itsconfigured DAP level is equal to or larger than the current broadcastNAP parameter, or if the current NAP parameter indicates theprioritization feature is disabled. If the configured DAP level is lessthan the current broadcast NAP parameter, the M2M device is still notallowed to initiate a network access.

Alternatively, the prioritization feature may be implemented in thefollowing manner:

The DAP level may be set for different class values where each classcorresponds to different M2M device characteristics. Thus, each M2Mdevice is configured to be a DAP class depending on each device'scharacteristics.

The network may broadcast one or more NAP classes in a broadcastoverhead message. If the M2M device's configured DAP class is equal toone of the NAP classes broadcast in the overhead message, the device isnot allowed to initiate network access for a period of time as mentionedabove. Alternatively, if the M2M device's configured DAP class is equalto one of the NAP classes broadcast in the overhead message, the deviceis allowed to initiate network access; otherwise not.

In a special case, if the device has data classified as “emergency” (forexample a “911” call or a call from an eHealth monitoring devicereporting a life-threatening event), the NAP/DAP checking mechanism maybe bypassed, and the device proceeds directly to persistence checking oris provided with priority access.

The disclosed network access priority control method can help to reduceor prevent an overload/congestion condition due to sudden externalevents. The disclosed method is a complement to the existing PersistenceTest mechanism, and when utilized together, forms a two-step process fornetwork access. The first step (the disclosed method) is to disqualifycertain devices and disallow these devices from initiating networkaccess. Those devices that pass the first step are allowed to initiatenetwork access and apply the Persistence Test mechanism to furthermitigate potential collision/congestion.

The disclosed method is applicable to any wireless communicationdevices, but it is especially useful for M2M devices, and particularlythose that are time/delay tolerant. This type of device (for example, autility meter) usually does not have critical data to send and cantolerate longer delays before sending its data to the network

In one embodiment, the present disclosure is directed to a method ofcontrolling access to a wireless Access Network (AN) by a wirelesscommunication device. The method includes the steps of storing in anon-transitory memory in the wireless communication device, a DeviceAccess Priority (DAP) level based on characteristics of the wirelesscommunication device; and when the wireless communication device hasdata to send, receiving by a radio receiver in the wirelesscommunication device, a message from the AN containing a Network AccessPriority (NAP) parameter, which defines a minimum priority level thatthe wireless communication device must meet to be allowed to initiatenetwork access. The method also includes determining by a processor inthe wireless communication device, whether the stored DAP level is equalto or greater than the NAP parameter received from the AN. When thestored DAP level is determined to be less than the NAP parameterreceived from the AN, the device periodically repeats the receiving anddetermining steps until the stored DAP level is determined to be equalto or greater than the NAP parameter received from the AN. When thestored DAP level is determined to be equal to or greater than the NAPparameter received from the AN, the device initiates network access. Theinitiating step may include performing the Persistence Test andtransmitting the data on an access channel (ACH) when the PersistenceTest is passed.

In another embodiment, the present disclosure is directed to a wirelesscommunication device configured to control access to a wireless AN. Thewireless communication device includes a non-transitory memoryconfigured to store a DAP level, wherein the DAP level is based oncharacteristics of the wireless communication device; and a radioreceiver configured to receive a message from the AN containing a NAPparameter when the wireless communication device has data to send. TheNAP parameter defines a minimum priority level that the wirelesscommunication device must meet to be allowed to initiate network access.The device also includes a processor configured to determine whether thestored DAP level is equal to or greater than the NAP parameter receivedfrom the AN. When the stored DAP level is determined to be less than theNAP parameter received from the AN, the device is configured toperiodically receive additional messages from the AN with new NAPparameters, and to determine whether the stored DAP level is equal to orgreater than one of the new NAP parameters received from the AN. Whenthe stored DAP level is determined to be equal to or greater than theNAP parameter received from the AN, the device is configured to initiatenetwork access.

The device may be configured to initiate network access by performingthe Persistence Test in which the processor generates a randompersistence value and determines that the device passed the PersistenceTest when the generated random persistence value is equal to or largerthan a persistence value assigned by the AN. When the wirelesscommunication device passes the Persistence Test, a radio transmitter inthe wireless communication device is configured to transmit on an accesschannel, the data the device has to send.

In a further embodiment, the present disclosure is directed to awireless Access Network (AN) configured to control access to the AN by awireless communication device, wherein the AN includes a processorcoupled to a non-transitory memory, wherein when the processor executescomputer program instructions stored in the memory, the processor causesthe AN to obtain traffic loading and congestion information for the AN;determine a value of a NAP parameter based on the traffic loading andcongestion information; and broadcast, utilizing a radio transmitter, anoverhead message to the wireless communication device, the overheadmessage containing the NAP parameter. The NAP parameter defines aminimum priority level that the wireless communication device must meetto be allowed to initiate network access.

In a further embodiment, the present disclosure is directed to a methodof controlling access to a wireless AN by a wireless communicationdevice. The method includes the steps of storing in a non-transitorymemory in the wireless communication device, a DAP class depending oncharacteristics of the wireless communication device; and when thewireless communication device has data to send, receiving by a radioreceiver in the wireless communication device, a message from the ANcontaining one or more prohibited NAP classes. A processor in thewireless communication device determines whether the stored DAP class isequal to any of the prohibited NAP classes received from the AN. Whenthe stored DAP class is equal to one of the prohibited NAP classesreceived from the AN, the device periodically repeats the receiving anddetermining steps until it is determined that the stored DAP class doesnot equal any of the prohibited NAP classes received from the AN. Whenthe stored DAP class does not equal any of the prohibited NAP classesreceived from the AN, the wireless communication device initiatesnetwork access.

In a further embodiment, the present disclosure is directed to a methodof controlling access to a wireless AN by a wireless communicationdevice. The method includes the steps of storing in a non-transitorymemory in the wireless communication device, a DAP class depending oncharacteristics of the wireless communication device; and when thewireless communication device has data to send, receiving by a radioreceiver in the wireless communication device, a message from the ANcontaining one or more allowed NAP classes. A processor in the wirelesscommunication device determines whether the stored DAP class is equal toany of the allowed NAP classes received from the AN. When the stored DAPclass does not equal any of the allowed NAP classes received from theAN, the device periodically repeats the receiving and determining stepsuntil it is determined that the stored DAP class is equal to one of theallowed NAP classes received from the AN. When the stored DAP class isequal to one of the allowed NAP classes received from the AN, thewireless communication device initiates network access.

Advantageously, the present disclosure improves on the existingPersistence Test with Backoff by also discriminating whether a deviceshould have higher or lower access priority from the applicationperspective. Additionally, instead of letting a device applicationdetermine its priority or access class, the solution provides fullnetwork control to address the congestion/overload condition. Thenetwork operator or service operator can use knowledge of different M2Mdevice characteristics and potential impact on network congestion tooptimally control network access priorities. The solution provides fullnetwork control and enough flexibility to mitigate network congestionsituations when very large numbers of devices are deployed in thecoverage area.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following section, the present disclosure will be described withreference to exemplary embodiments illustrated in the figures, in which:

FIG. 1 is a flow chart illustrating an exemplary embodiment of themethod of the present invention;

FIG. 2 is a signaling diagram illustrating another exemplary embodimentof the method of the present invention;

FIG. 3 is a signaling diagram illustrating another exemplary embodimentof the method of the present invention;

FIG. 3 is a signaling diagram illustrating another exemplary embodimentof the method of the present invention;

FIG. 5 is a flow chart illustrating an alternative exemplary embodimentof the method of the present invention;

FIG. 6 is a flow chart illustrating another alternative exemplaryembodiment of the method of the present invention;

FIG. 7 is a simplified block diagram of a wireless communication devicein an exemplary embodiment of the present invention; and

FIG. 8 is a simplified block diagram of a Network Access Priority (NAP)mechanism in the Access Network (AN) in an exemplary embodiment of thepresent invention.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth in order to provide a thorough understanding of the disclosure.However, it will be understood by those skilled in the art that thepresent disclosure may be practiced without these specific details. Inother instances, well-known methods, procedures, components and circuitshave not been described in detail so as not to obscure the presentdisclosure. It should be understood that the disclosure is describedprimarily in the context of a 3GPP cellular telephone/data network, butit can be implemented in other forms of cellular wireless networks aswell.

This disclosure relates to a system and method for controlling access toa wireless Access Network (AN) by wireless communication devices,particularly Machine-to-Machine (M2M) communication devices.

As noted above, the AN may broadcast the “Network Access Priority” (NAP)parameter in a Network overhead message. The exact structure of themessage depends on the Radio Access Technology (RAT) utilized in eachAN, but in each case the message includes a NAP field to indicate theNAP parameter. Examples of overhead messages that may be modified tocarry the NAP parameter include the System Information Block (SIB)message for Long Term Evolution (LTE) networks and theQuickConfig/SectorParameters message in High Rate Packet Data (HRPD)networks.

The NAP parameter is essentially a threshold that a device's DAP mustequal or exceed in order to attempt access. As the traffic load and thenumber of access attempts increase, the operator may increase the valueof the NAP parameter so that only higher priority devices are allowed toinitiate network access. As the traffic load and the number of accessattempts decrease, the operator may decrease the value of the NAPparameter so that lower priority devices, which were barred fromaccessing the network during the period of high traffic load, are nowallowed to initiate network access.

When network traffic is normal or light, the operator may choose todisable the prioritization feature entirely. This may be done, forexample, by broadcasting an overhead message that does not include a NAPparameter. Alternatively, the network may include the NAP parameter inthe overhead message, but set it to a default value indicating theprioritization feature is disabled. Subsequently, if the network loadincreases and access congestion occurs, the network can enable theprioritization feature by broadcasting a non-default NAP value in theoverhead message.

It should be noted that wireless/M2M devices that do not have a DeviceAccess Priority (DAP) level assigned ignore the NAP parameter. The DAPlevel may be assigned to an M2M device at different points in time. Forexample, the DAP level may be assigned to the device during apre-configuration stage; the service provider may pre-install the DAPlevel in the device before deployment; the DAP level may be assigned tothe device during session establishment or session update during thedevice's initial access to the network after installation; the M2Mdevice may be configured with the DAP level through over-the-airprovisioning or remote subscription management process; and the like.

Any M2M device that has the DAP level configured compares its DAP levelwith the NAP parameter received from the network. If the device's DAPlevel is equal to or greater than the NAP parameter, the device isallowed to initiate network access, and the Persistence Test mechanismis then performed to further determine whether the device can send dataon the ACH.

If the device's DAP level is less than the NAP parameter received fromthe network, the device is not allowed to initiate network access. Thedevice may wait for a period of time (either a randomly generated timeperiod or a pre-determined period of time) before rechecking the NAPparameter broadcast by the network and determining once again whetherits DAP level is equal to or greater than the NAP parameter. The NAP andDAP is compared again to determine whether the device is allowed toinitiate network access.

It should be noted that specification of the DAP level as being lessthan, equal to, or greater than the NAP parameter are described only forpurposes of illustration. More generally, the AN utilizes the NAPparameter to set conditions that an accessing communication device mustmeet before the device is allowed to initiate network access.

FIG. 1 is a flow chart illustrating an exemplary embodiment of themethod of the present invention. At step 11, the UE is configured with aDAP level identifying the UE's access priority from a networkperspective. At step 12, the AN sets the value of the NAP parameterbased on current loading/congestion conditions in the network. Ifnetwork loading/congestion conditions change, the AN may set a differentvalue for the NAP parameter. At step 13, the AN broadcasts an overheadmessage such as a SIB/QuickConfig message with the NAP parameter. Atstep 14, the UE, which has data to send, receives the overhead messageand detects the NAP parameter. Alternatively, the UE may receive theoverhead message containing the NAP parameter before having data tosend. In this case, the UE may store the NAP parameter and when the UEhas data to send, the UE compares the most current stored NAP parameterto the stored DAP value. This depends on the network design. For certainnetworks, the UE may not check the overhead message until it has data tosend, while in networks using other access technologies, the UE willperiodically receive overhead messages regardless of whether there isdata to send.

At step 15, the UE determines whether its configured DAP level is equalto or greater than the value of the NAP parameter received from the AN.If not, the method moves to step 16 where the UE may optionally start atimer defining either a predefined time period or a random time period.At step 17, it is determined whether the timer has expired. If not, theUE continues to wait until the timer expires at the end of the timeperiod. When the timer expires, the method returns to step 14, where theUE receives another overhead message.

The timer may be explicitly defined or implicitly defined. Whenimplicitly defined, the UE may periodically monitor the overhead message(or randomly based on an overhead message monitoring rule defined forthe access technology) such that the “timer” in this case is the timebetween two received overhead messages.

If it is determined at step 15 that the UE's configured DAP level isequal to or greater than the value of the NAP parameter received fromthe AN, the method moves to step 18 where the UE performs thePersistence Test. At step 19, it is determined whether the UE passed thePersistence Test. If not, the UE waits for the Backoff period at step 20and then performs the Persistence Test again. If the UE passed thePersistence Test, the method moves to step 21 where the UE sends itsdata on the ACH.

FIG. 2 is a signaling diagram illustrating another exemplary embodimentof the method of the present invention. In this embodiment, a UE 23 doesnot have a DAP level configured. The UE is initially in Idle Mode asindicated at 24 when the UE receives from an AN 25, an overhead message26 such as a SIB/QuickConfig message. As indicated at 27, the UE laterhas data to send to the network. However, since the UE is not configuredwith a DAP level, the UE ignores the NAP parameter received from the ANand performs the Persistence Test at step 28. When the UE passes thePersistence Test, the UE sends its data on the ACH at step 29.

FIG. 3 is a signaling diagram illustrating another exemplary embodimentof the method of the present invention. In this embodiment, a UE 31 hasa DAP level configured at level 3, and as indicated at 32, has data tosend to the network. When the UE receives the overhead message 26 fromthe AN 25 indicating a NAP parameter with a value of 2, the UEdetermines at step 33 that its configured DAP level is greater than thereceived NAP parameter. Therefore, at step 34, the UE performs thePersistence Test. When the UE passes the Persistence Test, the UE sendsits data on the ACH at step 35.

FIG. 4 is a signaling diagram illustrating another exemplary embodimentof the method of the present invention. In this embodiment, a UE 41 hasa DAP level configured at level 1, and as indicated at 42, has data tosend to the network. When the UE receives the overhead message 26 fromthe AN 25 indicating a NAP parameter with a value of 2, the UEdetermines at step 43 that its configured DAP level is smaller than thereceived NAP parameter, so the UE is not allowed to initiate networkaccess for a period of time (for example, a timer is initiated andcountdown started at step 44). When the time period expires, the UEreceives another overhead message 45 from the AN 25 indicating a NAPparameter with a new value of 1. At step 46, the UE determines that itsconfigured DAP level is equal to the new NAP parameter. Therefore, atstep 47, the UE performs the Persistence Test. When the UE passes thePersistence Test, the UE sends its data on the ACH at step 48.

FIG. 5 is a flow chart illustrating an alternative exemplary embodimentof the method of the present invention. At step 51, the UE is configuredwith a DAP class. The DAP level may be set for different class valueswhere different classes correspond to different M2M devicecharacteristics. Thus, each M2M device is configured to belong to a DAPclass depending on each device's characteristics. At step 52, the ANbroadcasts an overhead message such as a SIB/QuickConfig message withone or more prohibited NAP classes based on current networkloading/congestion conditions. When network loading/congestionincreases, the AN may set additional NAP classes as prohibited classes,and vice versa. At step 53, the UE, which has data to send, receives theoverhead message and detects the prohibited NAP classes.

At step 54, the UE determines whether its configured DAP class is equalto one of the prohibited NAP classes received from the AN. If so, themethod moves to step 55 where the UE waits for either a predefined timeperiod or a randomly generated time period. The method then returns tostep 53 where, the UE receives another overhead message and detects theprohibited NAP classes. If network loading/congestion conditions havechanged, the AN may broadcast more prohibited NAP classes (if networkloading/congestion has increased) or fewer prohibited NAP classes (ifnetwork loading/congestion has decreased) in the overhead message.

However, if it is determined at step 54 that the UE's configured DAPclass is not equal to any of the prohibited NAP classes received fromthe AN, the method moves to step 56 where the UE performs thePersistence Test. At step 57, it is determined whether the UE passed thePersistence Test. If not, the UE waits for the Backoff period at step 58and then performs the Persistence Test again. If the UE passed thePersistence Test, the method moves to step 59 where the UE sends itsdata on the ACH.

FIG. 6 is a flow chart illustrating an alternative exemplary embodimentof the method of the present invention. At step 61, the UE is configuredwith a DAP class as described in relation to FIG. 5 above. At step 62,the AN broadcasts an overhead message such as a SIB/QuickConfig messagewith one or more allowed NAP classes based on network loading/congestionconditions. When network loading/congestion increases, the AN may setfewer NAP classes as allowed classes, and vice versa. At step 63, theUE, which has data to send, receives the overhead message and detectsthe allowed NAP classes.

At step 64, the UE determines whether its configured DAP class is equalto any of the allowed NAP classes received from the AN. If not, themethod moves to step 65 where the UE waits for either a predefined timeperiod or a randomly generated time period. The method then returns tostep 63 where, the UE receives another overhead message and detects theallowed NAP classes. If network loading/congestion conditions havechanged, the AN may broadcast fewer allowed NAP classes (if networkloading/congestion has increased) or additional allowed NAP classes (ifnetwork loading/congestion has decreased) in the overhead message.

However, if it is determined at step 64 that the UE's configured DAPclass is equal to one of the allowed NAP classes received from the AN,the method moves to step 66 where the UE performs the Persistence Test.At step 67, it is determined whether the UE passed the Persistence Test.If not, the UE waits for the Backoff period at step 68 and then performsthe Persistence Test again. If the UE passed the Persistence Test, themethod moves to step 69 where the UE sends its data on the ACH.

FIG. 7 is a simplified block diagram of a wireless communication devicesuch as UE 23, 31, 41 in an exemplary embodiment of the presentinvention. The operation of the UE may be controlled by a processor 71executing computer program instructions stored on a non-transitorymemory. A radio receiver (RX) 72 receives the overhead message 26containing the NAP parameter from the AN 25 and supplies the NAPparameter to the processor. The processor reads the stored DAP levelfrom a memory 73 and compares the stored DAP level with the received NAPparameter in a DAP/NAP comparison unit 74. In accordance with the methodembodiments described above, if the DAP does not meet the NAPconditions, the UE is not allowed to make an access attempt. A DAP/NAPtimer 75 determines when the UE can receive another overhead message andperform the DAP/NAP comparison again.

When the UE determines the DAP level meets the NAP parameter conditions(for example, the DAP level is equal to or greater than the NAPparameter), the processor 71 causes a Persistence Test unit 76 toperform the Persistence Test. If the test is not passed, a Backoff timer77 determines when the UE can perform the Persistence Test again. Whenthe Persistence Test is passed, the processor causes a radio transmitter(TX) 78 to transmit the UE's data on the ACH 79 to the AN 25.

FIG. 8 is a simplified block diagram of a NAP mechanism 80 in the AN 25in an exemplary embodiment of the present invention. The NAP mechanismis illustrated in this example as being implemented in a Radio BaseStation (RBS) 81, but may be implemented in other ways as well. Forexample, the NAP mechanism may be implemented in a Base StationController (BSC) (not shown), may be distributed across several ANnodes, or may be implemented as a standalone AN component.

Operation of the NAP mechanism may be controlled by a processor 82executing computer program instructions stored on a non-transitorymemory. A Loading/Congestion determining unit 83 provides information tothe processor regarding the network traffic loading and congestion onthe ACH 79. The processor may control a NAP determining unit 84 todetermine an appropriate NAP parameter based on the networkloading/congestion. The processor sends the NAP parameter to a radiotransmitter (TX) 85, which transmits the NAP parameter in the overheadmessage 26. Once the UE has successfully performed the DAP/NAPcomparison and the Persistence Test, a radio receiver (RX) 86 in the RBSreceives the UE's data on the ACH and supplies it to the processor 82.The processor may forward the data to other nodes in the AN forhandling.

If the device has data classified as “emergency”, the NAP/DAP checkingmechanism may be bypassed in any of the above embodiments.

As will be recognized by those skilled in the art, the innovativeconcepts described in the present application can be modified and variedover a wide range of applications. Accordingly, the scope of patentedsubject matter should not be limited to any of the specific exemplaryteachings discussed above, but is instead defined by the followingclaims.

What is claimed is:
 1. A method of controlling access to a wirelessAccess Network (AN) by a wireless communication device, the methodcomprising the steps of: storing in a non-transitory memory in thewireless communication device, a Device Access Priority (DAP) levelbased on characteristics of the wireless communication device; when thewireless communication device has data to send, receiving by a radioreceiver in the wireless communication device, a message from the ANcontaining a Network Access Priority (NAP) parameter, which defines aminimum priority level that the wireless communication device must meetto be allowed to initiate network access; determining by a processor inthe wireless communication device, whether the stored DAP level is equalto or greater than the NAP parameter received from the AN; when thestored DAP level is determined to be less than the NAP parameterreceived from the AN, periodically repeating the receiving anddetermining steps until the stored DAP level is determined to be equalto or greater than the NAP parameter received from the AN; and when thestored DAP level is determined to be equal to or greater than the NAPparameter received from the AN, initiating network access by thewireless communication device.
 2. The method as recited in claim 1,wherein the AN periodically sets a value of the NAP parameter based oncurrent network loading or congestion conditions.
 3. The method asrecited in claim 2, wherein the AN sets a higher value for the NAPparameter when the network loading or congestion conditions increase. 4.The method as recited in claim 1, wherein the step of initiating networkaccess by the wireless communication device includes the steps of:performing a Persistence Test in which the processor generates a randompersistence value and determines that the device passed the PersistenceTest when the generated random persistence value is equal to or largerthan a persistence value assigned by the AN; and when the wirelesscommunication device passes the Persistence Test, transmitting on anaccess channel by a radio transmitter in the wireless communicationdevice, the data the device has to send.
 5. The method as recited inclaim 1, wherein the wireless communication device is aMachine-to-Machine (M2M) communication device.
 6. The method as recitedin claim 1, wherein the AN is a Long Term Evolution (LTE) accessnetwork, and the message received from the AN is a broadcast overheadmessage comprising a System Information Block (SIB) message.
 7. Themethod as recited in claim 1, wherein the AN is a High Rate Packet Data(HRPD) network, and the message received from the AN is a broadcastoverhead message comprising a QuickConfig/SectorParameters message.
 8. Awireless communication device configured to control access to a wirelessAccess Network (AN), the wireless communication device comprising: anon-transitory memory configured to store a Device Access Priority (DAP)level, wherein the DAP level is based on characteristics of the wirelesscommunication device; radio receiver configured to receive a messagefrom the AN containing a Network Access Priority (NAP) parameter whenthe wireless communication device has data to send, wherein the NAPparameter defines a minimum priority level that the wirelesscommunication device must meet to be allowed to initiate network access;and a processor configured to determine whether the stored DAP level isequal to or greater than the NAP parameter received from the AN; whereinwhen the stored DAP level is determined to be less than the NAPparameter received from the AN, the device is configured to periodicallyreceive additional messages from the AN with new NAP parameters, and todetermine whether the stored DAP level is equal to or greater than oneof the new NAP parameters received from the AN; and wherein when thestored DAP level is determined to be equal to or greater than the NAPparameter received from the AN, the device is configured to initiatenetwork access.
 9. The wireless communication device as recited in claim8, wherein the device is configured to: initiate network access byperforming a Persistence Test in which the processor generates a randompersistence value and determines that the device passed the PersistenceTest when the generated random persistence value is equal to or largerthan a persistence value assigned by the AN; and when the wirelesscommunication device passes the Persistence Test, transmit on an accesschannel by a radio transmitter in the wireless communication device, thedata the device has to send.
 10. The communication device as recited inclaim 8, wherein the wireless communication device is aMachine-to-Machine (M2M) communication device.
 11. A wireless AccessNetwork (AN) configured to control access to the AN by a wirelesscommunication device, wherein the AN includes a processor coupled to anon-transitory memory, wherein when the processor executes computerprogram instructions stored in the memory, the processor causes the ANto: determine traffic loading and congestion conditions for the AN;determine a value of a Network Access Priority (NAP) parameter based onthe traffic loading and congestion conditions, the NAP parameterdefining a minimum priority level that the wireless communication devicemust meet to be allowed to initiate network access; and broadcast,utilizing a radio transmitter, an overhead message to the wirelesscommunication device, the overhead message containing the NAP parameter.12. The AN as recited in claim 11, wherein a NAP determining unit isconfigured to set a higher value for the NAP parameter when the networkloading or congestion conditions increase.
 13. The AN as recited inclaim 11, wherein a NAP determining unit is configured to set the NAPparameter to zero or omit the NAP parameter from the overhead messagewhen the network loading is light.
 14. The AN as recited in claim 11,wherein the AN is a Long Term Evolution (LTE) access network, and theoverhead message comprises a System Information Block (SIB) message. 15.The AN as recited in claim 11, wherein the AN is a High Rate Packet Data(HRPD) network, and the overhead message comprises aQuickConfig/SectorParameters message.
 16. A method of controlling accessto a wireless Access Network (AN) by a wireless communication device,the method comprising the steps of: storing in a non-transitory memoryin the wireless communication device, a Device Access Priority (DAP)class depending on characteristics of the wireless communication device;when the wireless communication device has data to send, receiving by aradio receiver in the wireless communication device, a message from theAN containing one or more prohibited Network Access Priority (NAP)classes; determining by a processor in the wireless communicationdevice, whether the stored DAP class is equal to any of the prohibitedNAP classes received from the AN; when the stored DAP class is equal toone of the prohibited NAP classes received from the AN, periodicallyrepeating the receiving and determining steps until it is determinedthat the stored DAP class does not equal any of the prohibited NAPclasses received from the AN; and when the stored DAP class does notequal any of the prohibited NAP classes received from the AN, initiatingnetwork access by the wireless communication device.
 17. The method asrecited in claim 16, wherein the AN periodically sets the prohibited NAPclasses based on current network loading or congestion conditions. 18.The method as recited in claim 17, wherein the AN sets additionalprohibited NAP classes when the network loading or congestion conditionsincrease, and sets fewer prohibited NAP classes when the network loadingor congestion conditions decrease.
 19. The method as recited in claim17, wherein the AN indicates there are no prohibited NAP classes whenthe network loading is light.
 20. A method of controlling access to awireless Access Network (AN) by a wireless communication device, themethod comprising the steps of: storing in a non-transitory memory inthe wireless communication device, a Device Access Priority (DAP) classdepending on characteristics of the wireless communication device; whenthe wireless communication device has data to send, receiving by a radioreceiver in the wireless communication device, a message from the ANcontaining one or more allowed Network Access Priority (NAP) classes;determining by a processor in the wireless communication device, whetherthe stored DAP class is equal to any of the allowed NAP classes receivedfrom the AN; when the stored DAP class does not equal any of the allowedNAP classes received from the AN, periodically repeating the receivingand determining steps until it is determined that the stored DAP classis equal to one of the allowed NAP classes received from the AN; andwhen the stored DAP class is equal to one of the allowed NAP classesreceived from the AN, initiating network access by the wirelesscommunication device.
 21. The method as recited in claim 20, furthercomprising detecting by the wireless access device that the AN haschanged the allowed NAP classes based on current network loading orcongestion conditions.
 22. The method as recited in claim 21, whereinthe step of detecting that the AN has changed the allowed NAP classesincludes the steps of: detecting that the AN has set fewer allowed NAPclasses due to increased network loading or congestion conditions; anddetecting that the AN has set additional allowed NAP classes due todecreased network loading or congestion conditions.